As computers get more powerful and 3D rendering software more sophisticated, computers are being used more and more in the creation of photo real images and animation. This computer generated imagery is replacing photography and cinematography in the real world for making images of new product designs, such as consumer goods and cars for marketing and advertising, or for creating virtual characters and visual effects in movies.
The ingredients required to make these images using a computer are 3D geometry representing the physical forms of the objects being visualised, shaders that describe the appearance of the geometry (the materials), virtual cameras which specify the views that are being rendered and finally the light sources creating the illumination. All of these elements are generally contained within a computer file called a ‘scene’ that can be opened by a 3D software package. 3D software packages let the user create/assemble and adjust these ingredients and then compute images using this data.
In 3D software the scene is represented and interacted with via viewports. These viewports act as windows onto the scene; either views through the cameras, or importantly orthographic views like front, side and top. An example of a typical user interface in existing 3D software is shown in FIG. 1. Users can move around these views; so rotate the camera, zoom in and out. With the orthographic views users can only move up, down, left, and right on a plane and zoom in and out, they are locked to the orthographic projection. The user needs to use all of these different viewports to accurately position objects with the scene. Objects are first selected and then tools used to move their position. The users swaps to the top view to understand the relative position of the objects in the plan view, then the user swaps to the side view to check the height they are placing objects. Placing objects in 3D space using the cameras view is virtually impossible as the user doesn't have the ability to judge height and depth. Using the front, side and top views are essential for placing objects and light sources within a scene.
Until recently these viewports would have been always shown in wireframe or with simple shading. A wireframe view is far faster to compute and this simple representation of the scene enables users to more easily find and interact with the objects when they a represented in this simple manner. Additionally traditional CG lights are represented with icons to show their position, direction, scale, type. These icons could be moved like any other object within the scene. But the CG lights had no physical form, so the icons were needed as a way to place and interact with the lights.
As computing power has increased, only recently has it become common place to have a fully rendered interactive viewport with the real world physical behaviour of lighting transport, reflections and materials delivering an image in real-time, or near real-time, with a quality and feel that is very close to the final production quality rendering. This viewport can be called a ‘virtual interactive photograph’, where changes to the scene update the virtual photograph straight away. An example of the user interface that includes a real-time rendered view, as well as orthographic views, is shown in FIG. 2.